Open-Riser Staircase Safety: Metal Stringer Design Guide

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An open-riser staircase with metal stringers is safe when the stringers are sized for the load and span, the treads are fixed securely, and the openings meet the rules for gaps and railing heights. Good design also considers how a child or pet might pass through the open spaces and how the balustrade is anchored. Exact values should always be confirmed with the structural engineer and the applicable Israeli standard.

Why open risers change the safety picture

An open-riser staircase removes the vertical board between treads, which gives a light, floating look that many modern homes want. The trade-off is that the open space between treads becomes part of the safety design. Feet can slip through, small children can get a leg or head caught, and a dropped object can fall through to the floor below.

Because nothing closes the gap, every decision about the stringers, treads, and railing carries more weight. The structure must feel rigid and the openings must be controlled from the first sketch.

Metal stringer strength and span

In an open-riser stair, the stringers carry the entire load of the treads, so their size, material, and fixing points matter most. Steel and aluminum stringers each behave differently under load and over long spans, and the choice should be based on a structural check rather than appearance alone.

Confirm the stringer profile and thickness with the engineer for the specific span.
Check deflection so the stair does not feel bouncy underfoot.
Plan connections at the top and bottom landings carefully.

Tread fixing and the feel underfoot

Treads on an open-riser staircase are often visible from the side, so the way they connect to the stringers should be clean but still very secure. Hidden or semi-hidden fixings can keep the look minimal while giving a firm, solid step.

Consider the tread material and its grip. Surfaces that are too smooth can be slippery, especially when wet, so finish and texture should be chosen with safety in mind as well as style.

Controlling openings and gaps

The open area between treads and between the stringer and the stair edge must be checked against the safety rules for openings. A common concern is that a small child could pass through a gap, so designers usually limit the size of openings and look at the geometry of the whole staircase, not one step at a time.

Where a stair is near a wall, or where a second stair runs alongside, check the sightlines and gaps together. Exact allowable dimensions should be confirmed against the current standard rather than estimated from memory.

Balustrade and handrail considerations

The railing is the main protection on an open staircase, so it needs to be continuous, rigid, and at the correct height. Many designers choose glass infill or slim metal bars to keep the view open while still meeting the protective function.

The Israeli railing standard SI 1142 sets the general framework for railings, and the engineer should confirm the specific heights, loads, and infill spacing for the project. A handrail on at least one side is commonly expected and is also useful for everyday use.

Installation, finishing, and inspection

Even a well-designed stair can become unsafe if anchors are weak or the metal is not finished properly. Anchors into concrete or masonry should be set to the engineer's details, and finishes such as hot-dip galvanizing or powder coating help protect the steel over time.

Check anchor embedment and fixing details on site.
Inspect welds and connections before final finishing.
Test the stair for movement and stability after installation.

Frequently asked questions

Are open risers allowed in Israeli homes?

Open risers can be used in residential projects when the design meets the relevant building and safety requirements. Confirm the specific rules for your project with the structural engineer and local approval process.

What makes metal stringers suitable for open-riser stairs?

Metal stringers can carry loads over clean spans with slim profiles, which suits the open look. The section size and connections must be checked by an engineer for each project.

Is a glass railing safe on an open staircase?

A glass railing can be safe when it is designed, fixed, and installed to the correct loads and heights. The glass type and fixings should be specified by the engineer.

Who should check an open-riser staircase design?

A structural engineer should check the stringers, connections, and loads, and the design should follow the Israeli standards that apply. Your architect or designer can coordinate this with the metalwork specifications.

Common mistakes to avoid

Designers often focus on the look of open treads and forget to check the gaps, the railing height, and the stringer loads together. Leaving these checks until installation can force costly changes to a finished staircase.

Our recommendation

Involve the engineer and the metalwork manufacturer early, before the final drawings are fixed. Share the design intent, the floor plan, and any child or pet safety concerns so the stringers, openings, and railings are planned as one system.

Summary

Open-riser staircases with metal stringers can be both striking and safe when span, gaps, tread fixing, and railings are designed together. Confirm exact values with the engineer and the applicable standard.

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